From: Michihiro NAKAJIMA <ggcueroad@gmail.com>
Date: Fri, 2 Nov 2012 06:21:48 +0000 (+0900)
Subject: Cancel HFS+ compression if the compressed size is not enouph small.
X-Git-Tag: v3.1.0~39^2~22
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8f7fbd41dd55a2b0ab4808ba3854c1585166c8b9;p=thirdparty%2Flibarchive.git

Cancel HFS+ compression if the compressed size is not enouph small.
---

diff --git a/libarchive/archive_write_disk_posix.c b/libarchive/archive_write_disk_posix.c
index a522d9c8a..90c82c51a 100644
--- a/libarchive/archive_write_disk_posix.c
+++ b/libarchive/archive_write_disk_posix.c
@@ -322,6 +322,7 @@ struct archive_write_disk {
 #define DECMPFS_UNCOMPRESSED_SIZE	8
 #define DECMPFS_HEADER_SIZE		16
 
+#define HFS_BLOCKS(s)	((s) >> 12)
 
 static int	check_symlinks(struct archive_write_disk *);
 static int	create_filesystem_object(struct archive_write_disk *);
@@ -1033,6 +1034,67 @@ hfs_reset_compressor(struct archive_write_disk *a)
 	return (ARCHIVE_OK);
 }
 
+static int
+hfs_decompress(struct archive_write_disk *a)
+{
+	uint32_t *block_info;
+	unsigned int block_count;
+	uint32_t data_pos, data_size;
+	ssize_t r;
+	ssize_t bytes_written, bytes_to_write;
+	unsigned char *b;
+
+	block_info = (uint32_t *)(a->resource_fork + RSRC_H_SIZE);
+	block_count = archive_le32dec(block_info++);
+	while (block_count--) {
+		data_pos = RSRC_H_SIZE + archive_le32dec(block_info++);
+		data_size = archive_le32dec(block_info++);
+		r = fgetxattr(a->fd, XATTR_RESOURCEFORK_NAME,
+		    a->compressed_buffer, data_size, data_pos, 0);
+		if (r != data_size)  {
+			archive_set_error(&a->archive,
+			    (r < 0)?errno:ARCHIVE_ERRNO_MISC,
+			    "Failed to read resource fork");
+			return (ARCHIVE_WARN);
+		}
+		if (a->compressed_buffer[0] == 0xff) {
+			bytes_to_write = data_size -1;
+			b = a->compressed_buffer + 1;
+		} else {
+			uLong dest_len = MAX_DECMPFS_BLOCK_SIZE;
+			int zr;
+
+			zr = uncompress((Bytef *)a->uncompressed_buffer,
+			    &dest_len, a->compressed_buffer, data_size);
+			if (zr != Z_OK) {
+				archive_set_error(&a->archive,
+				    ARCHIVE_ERRNO_MISC,
+				    "Failed to decompress resource fork");
+				return (ARCHIVE_WARN);
+			}
+			bytes_to_write = dest_len;
+			b = (unsigned char *)a->uncompressed_buffer;
+		}
+		do {
+			bytes_written = write(a->fd, b, bytes_to_write);
+			if (bytes_written < 0) {
+				archive_set_error(&a->archive, errno,
+				    "Write failed");
+				return (ARCHIVE_WARN);
+			}
+			bytes_to_write -= bytes_written;
+			b += bytes_written;
+		} while (bytes_to_write > 0);
+	}
+	r = fremovexattr(a->fd, XATTR_RESOURCEFORK_NAME, 0);
+	if (r == -1)  {
+		archive_set_error(&a->archive, errno,
+		    "Failed to remove resource fork");
+		return (ARCHIVE_WARN);
+	}
+	return (ARCHIVE_OK);
+}
+
 static int
 hfs_drive_compressor(struct archive_write_disk *a, const char *buff,
     size_t size)
@@ -1155,6 +1217,7 @@ fprintf(stderr, "block %u bytes --> %u bytes in resource fork\n", (unsigned)size
 	 */
 	if (a->file_remaining_bytes == 0) {
 		size_t rsrc_size;
+		int64_t bk;
 
 		/* Append the resource footer. */
 		rsrc_size = hfs_set_resource_fork_footer(
@@ -1162,6 +1225,15 @@ fprintf(stderr, "block %u bytes --> %u bytes in resource fork\n", (unsigned)size
 		    a->compressed_buffer_remaining);
 		ret = hfs_write_compressed_data(a, bytes_used + rsrc_size);
 		a->compressed_buffer_remaining = a->compressed_buffer_size;
+
+		/* If the compressed size is not enouph smaller than
+		 * the uncompressed size. cancel HFS+ compression.
+		 * TODO: study a behavior of ditto utility and improve
+		 * the condition to fall back into no HFS+ compression. */
+		bk = HFS_BLOCKS(a->compressed_rsrc_position);
+		bk += bk >> 7;
+		if (bk > HFS_BLOCKS(a->filesize))
+			return hfs_decompress(a);
 		/*
 		 * Write the resourcefork header.
 		 */